In membranes used for water treatment, membrane fouling occurs as membranes are used for a long period of time, and there occur problems in a decrease in water permeation flow rate due to membrane fouling and safety due to a long-term operation. Moreover, these problems also cause an increase in overall operation costs of the membrane.
Accordingly, various methods are used in order to reduce membrane fouling. Examples of a representative method for reducing membrane fouling include a surface-coating method of a hydrophilic material and a chemical grafting method.
The surface-coating method of the hydrophilic material has an advantage in that the membrane has excellent fouling resistance during the initial period of operation, but has a disadvantage in that there occurs a phenomenon in which a coating layer is peeled off from the membrane during a long-period operation or when the membrane is chemically cleaned for the continuous use of the membrane.
Further, the chemical grafting method has an advantage in that the method has excellent long-period stability compared to the surface coating method of a hydrophilic material, but has a disadvantage in that reaction conditions are stringent and it is difficult to obtain a large area.
Accordingly, it may be considered to develop a technology of modifying the surface of a membrane, which may overcome the disadvantages present in the methods in the related art and improve performance of the membrane.